A/C servicing; vacuum, oil and charge system? (1 Viewer)

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You guys crack me up, next thing you know, P is going to have a digital dead weight and a certified master gauge on his bench.
 
https://jmtest.com/vaetrix/ you don't want one. I'm only joking of course. There isn't a real way to accurately test or measure gas lines with another gas. There are only degrees of accuracy. Not to nitpick.
 
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@flintknapper Would you please clarify. In and earlier post where you instructed me "you don't want your low side valve completely open at this point" You're speak about Low valve on manifold correct?

"The remaining cans (we are really looking to 'weigh in' the charge) will be introduced though the Low Side port in a gaseous (NOT LIQUID) state, so the keep the can upright. Engine running, HIGH SIDE OFF, low side open, compressor running, A/C set on high. This will be a slower process and you don't want your low side valve completely open at this point. Just open it enough that you see the pressure rise (it might jump around a bit) to no more than 60-80 psi. It will drop some as the system stabilizes."

https://jmtest.com/vaetrix/ you don't want one. I'm only joking of course. There isn't a real way to accurately test or measure gas lines with another gas. There are only degrees of accuracy. Not to nitpick.
I was aware you were joking. Ergo the LOL.

They are not the same.
Thanks @medtro. Lucky I drove the rig to NAPA, as we had to pull the schrader valves and match them up. My old looked like new and further test (pulling vac) didn't reveal they leak, but replaced anyway.
NAPA PN # 409914.
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I replaced the Dryer, again using a Denso 478-1500. This time I found (in the Canadian 00LX) two piece aluminium plug with double O-rings and plastic filter, so that's what I used here. Earlier in the thread the 07LC had the one piece plastic plug w/single O-ring & filter. So I'm wondering if this was factory or a replacement. No record in history of being replaced.
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Filter was gunked up on this one. The system history indicates into Lexus twice for charging, but didn'T specify if stop leak used.
What could it be?
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Old Double O-rings look ok.
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@flintknapper Would you please clarify. In and earlier post where you instructed me "you don't want your low side valve completely open at this point" You're speak about Low valve on manifold correct?

Yes, at the manifold. If you open it all the way...then you are probably going to see the pressure (low side) jump way up, freak out...stop charging and be back here with questions...so I just advise folks to 'control' the amount of refrigerant going in (especially the second can). The last can (or remaining ounces of refrigerant) will be harder to get into the system..so at THAT point open your low side manifold gauge all the way and even be prepared to tilt the can 'briefly' a few times as well.

Just trying to save you some trouble. You've got it on the run.
 
I really appreciate it too, and is how I did the first time around. Since vacuum was confirmed holding, I was just reviewing before replacing receiver, scharders and charging.

Darned if a new schrader valve didn't leak/stick, as I tested after a 4 hour vac. Probably was my fault, for getting NyLog on both upper and lower O-ring. Or perhaps it was damaged. Either way I tossed and old one back on.

Hey @flintknapper what's your thought on the receiver filter gunk?
 
Hey @flintknapper what's your thought on the receiver filter gunk?

Anybody's guess. But certainly an element that has broken down.

Some possibilities:

System previously 'flushed', flushing agent not completely removed.
Broken down dye or stop leak product.
Remnants of severely heated lubricating oil (previous compressor failure).

Sometimes a desiccant bag will rupture....but that is usually brown or gray looking and sort of like powdered sediment. So probably not that.

I can't really say, except it doesn't belong there.
 
@2001LC how many cans did you go thru? Mine used 2.5 to reach correct pressure at around 35.


When recharging a completely empty system...we will do better to 'weigh in' the recommended charge than to look for a specific pressure.

We DO want to use our gauges to monitor the system and when used in conjunction with a temperature measuring device at the A/C vent, determine the 'optimum' charge.

Often times...you will read someone state that low side pressure should be (X) and high side pressure (Y) while completely ignoring the ambient temperature which affects what the correct Pressure/Temperature should be.

The safest place to 'start' is to weigh in the charge the engineers have determined to be correct for that system (using OEM components or their equivalent). Then use your gauges to monitor the pressures (keeping them within an acceptable pressure window) while increasing or decreasing the charge slightly to see what gives you the best vent temps if you really want to tweak it.

The real value of having a set of manifold gauges is for diagnostic work and for charging systems that need only a 'partial' (top off) charge.
 
This is what mine looked like next to new. Id say it was original.

View attachment 1790473

View attachment 1790474
Lexus/Toyota history & parts records did not indicate dyer being replaced in this 00LX w/357Km nor in the 07LC w/127K miles done in June. So I'll assume factory switch to the plastic one piece sometime after 2001 and we're both seeing factory installed two piece with double O-ring.

Anybody's guess. But certainly an element that has broken down.

Some possibilities:

System previously 'flushed', flushing agent not completely removed.
Broken down dye or stop leak product.
Remnants of severely heated lubricating oil (previous compressor failure).

Sometimes a desiccant bag will rupture....but that is usually brown or gray looking and sort of like powdered sediment. So probably not that.

I can't really say, except it doesn't belong there.
Thank you, that's what I wanted to know "I can't really say, except it doesn't belong there". I didn't know if age alone could produce this.

History of Lexus maintained states at first evac & charge: "Not blowing as cold in slow traffic as as on HWY. System .5 low recharge with 2.45. Parts list: 2 002630013401 r134w warranty.

Next recharge a yr later in 2015 with much less info and nothing on parts list. Again note of service dep indicated "cool" just not cold.

So I'm guessing someone added dye and or stop leak at second recharge or the son sometime after. As son had the rig for last two years possible had done elsewhere as Lexus history of service stop with his taking over ownership.


@2001LC how many cans did you go thru? Mine used 2.5 to reach correct pressure at around 35.
On The 07LC I did in June, I used three cans of 12 os (36 oz) This is right at minimum system calls for.

I' put one can in the High side this morning. I'm going out now that it's settled to high side, to work on getting in two more cans in low side. OAT is going to by 92 F today so my Garage my hit 100 F with engine running to get into low side. So I may not get very good pressure reading or bubble test in sight glass until it cools at bit.

But regardless I'll be doing like last time and as @flintknapper states 'weigh in" I'm going to really work at getting all 3 cans in.

When recharging a completely empty system...we will do better to 'weigh in' the recommended charge than to look for a specific pressure.

We DO want to use our gauges to monitor the system and when used in conjunction with a temperature measuring device at the A/C vent, determine the 'optimum' charge.

Often times...you will read someone state that low side pressure should be (X) and high side pressure (Y) while completely ignoring the ambient temperature which affects what the correct Pressure/Temperature should be.

The safest place to 'start' is to weigh in the charge the engineers have determined to be correct for that system (using OEM components or their equivalent). Then use your gauges to monitor the pressures (keeping them within an acceptable pressure window) while increasing or decreasing the charge slightly to see what gives you the best vent temps if you really want to tweak it.

The real value of having a set of manifold gauges is for diagnostic work and for charging systems that need only a 'partial' (top off) charge.
Weigh in is how I did and doing today.

In hindsight I messed up. I added oil to yellow hose then connect bottle for high side fill. Then bled off air at yellow hose schrader valve at manifold. This didn't go well, as I think I lost most all the oil as I bleed out a lot out of concern I may have air behind oil. I should have added oil through ports as I swapped out schrader valves, then let it rest before vacuuming. Duh!

I did add some oil to dyier during install. I'll add oil again to yellow line with each of the next two cans, then connect a can but keep needle valve down after puncher. I'll keep yellow hose lower than manifold end of hose with can at low point. This should let oil settle at bottom and air at top, if I give 'say' 10 minutes to settle. Then this time I'll only bleed just a tiny bit.
 
So three 12 oz cans in (less spillage)

1st 12 oz can in High port engine off, took about 15 minutes.

Can 2 and 3 went into low port with RPM ~1,500, took about 50 and 40 minutes (shook 2nd can more often than first).
Sight glass turn clear after about 2 1/2 cans. Low gauge read 36 PSI & High 280 PSI as last oz went in with OAT of 108 F
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Once done charging, I ran RPM at 2,000 then turned off A/C. A few seconds after A/C turned off, sight glass foamed for about 17 seconds, then turned clear again.


It was hot in the garage today. I did this A/C charge mid afternoon during record breaking heat in Denver. Garage reached 108 f engine coolant temp hit 190 F with intake air temp hitting 141 F. So I'll check PSI of L & H with manifold later when OAT of garage cooler.
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Third can in A/C turned off engine idling now.
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A/C blows very cold.:cool:
 
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I've got a problem with High pressure 250 to 275 PSI

I rechecked today with OAT of 93 F in shop. Air at intel for HVAC may have been a bit hotter from heat of engine.

Why is my "H" pressure so high, ranging 250 to 275 PSI?

Would volume of oil affect pressure, say if to much would it raise pressure?

Is there any danger of damaging system with these pressures?

Should I bleed some off from H side engine off, L side or just see if it hold these pressures?

FSM (if I did my MPa to PSI conversion correctly) is:
L 21.33 to 35.55 PSI
H 199 to 213.33 PSI

Low stabilized at max recommended ~35 to 35.5 PSI so good pressure there. But high is ranging 37 to 62 PSI over max.
Considering spillage, I put in less than 36 oz R134a in system. Minimum is 35.2, so I'd be right about minium. This assumes each can had the stated 12 oz.

Hooked up manifold with A/C on full, windows open, RPM 2K. At first engine was not quite yet to operating temp, A/C just turned on I get reads of L 37.5, H 275 PSI
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Over next few minutes "L" pressure stabilized at 35 to 35.5 PSI. High dropped also, but only to 250 PSI then climb some to 275 PSI moving around a bit.

After about 5 minutes seem to stabilize around L 35, H 260
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You have PM Sir.
 
I used 2.5 - 2.75 cans, I watched the gauge and made sure I didn’t go past 35 L and 225 H. Your numbers seem high to my untrained eye but that could be due to your OAT and elevation? Like you the last bit took a while to empty.

Curious what you two find out. Can you report back?
 
I calculate high side from the book to be.
1.37 to 1.57 MPa is 200-225 psig.
ambient air temp 86-95°F engine at 1500rpm. That's what I test at, and add at. I wouldn't mind knowing a plus or minus number high and low that's acceptable. Another thing not accounted for is gauge accuracy %.
I only add or check with those ambient temps from the book. That's easy down here.

What is the effect of adding the air slug into the system over time from your hose train if you forget to bleed off air from the hoses?
What is the relationship between outside temp and gauge pressures while compressor is loaded, or loadING
I have a leak. I'm trying to figure that out. My high side pressure is never above 225psig at high humidity, ambient at 85+°F
 
@flintknapper are in agreement, I should just watch for now. That it is not so high as to cause damage. My high OAT (which was probable higher than stated) would yield higher readings on gauge IIRC. He also said if I got air in system this would kick up pressure. Also as noted, I used stated weight on cans not actual weight.

Bottom line it's blowing very cold.:cool:

I'll be doing some more testing with IR gun for temp readings and manifold for pressures. I'll report back here.
 
Where is the receiver/dryer?? What tools does one need to get it replaced and i assume it goes in whole bag?
 
Where is the receiver/dryer?? What tools does one need to get it replaced and i assume it goes in whole bag?
Post # 29. 10mm hex socket IIRC. Yes whole bag.
 

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